Electrical switch



1961 I H. E. ROMMEL 2,972,661

ELECTRICAL SWITCH Filed Nov. 15, 1958 an. 33 LP 21 u INVENTOR- flo a1 d Wom/nw United States Patent ELECTRICAL SWITCH Howard E. Rommel, Easton, Conn. (R.F.D. 1, Box 583, Bridgeport, Conn.)

Filed Nov. 13, 1958, Set. Na. 773,715

1 Claim. (Cl. 2005) This invention relates to apparatus comprising an electrical normally closed multiple contact switch associated with a plurality of releasably fixed switch trip dogs capable of being expanded to accurately adjust the switch trip surfaces of the trip dogs while being releasably fixed to a support. This apparatus is to be used in conjunction with a pending application Serial No. 772,199, filed November 6, 1958, for an Automatic Control System for Machines.

Ordinarily, the accuracy that can be obtained in the operation of machine tools, and particularly in the automatic cycle operation of machine tools is limited by the accuracy that can beobtained with certain elements of the automatic control. For example, when electrical circuits are employed to control the extent of movement of a member, the accuracy of termination of the movement of the member is limited because of the high voltage required as contrasted to electronic circuitry employing a low signal voltage and also the degree of accuracy of.

termination of a movable member is limited by the machine induced vibration of resiliently mounted switch trip dogs mounted on fine wires of certain prior known systems. Also the complexity of operating parts of these prior known electric switches induces inaccuracies in the repetitive operation of these prior known switches.

Objects of the present invention include the provision of a simply constructed, accurate, and compact electrical switch having a plurality of contacts and a plurality of expandable switch trip dogs associated with the multiple switch for operating the plurality of contacts where the trip surfaces of the dogs are capable of being accurately expanded while being releasably fixed to a support and the provision of such a switch which can be operated with equal facility by a movable member approaching it from either of two directions.

The above, as well as other objects and novel features of the invention will become apparent from the following specifications and accompanying drawing in which:

Figure l' is an elevational view of an electrical switch to which the principles of the present invention have been applied;

Fig. 2 is a view of the apparatus shownin Figure l, as viewed when looking in the direction of the arrows 22 of Figure 1.

The embodiment disclosed in the present case deals with the employment of a relatively large number of switches arranged in closely spaced relation, and to separate actuators for each set of contacts, which later are adjustable throughout the entire path of travel of a movable member controlled by the operation of the sets of contacts.

Referring to Figure 1 and Figure 2, ribs 30 and 31 of support are spaced sutnciently to provide for adjust- 2,972,661 Patented Feb. 21, 1961 ing a trip dog 12' an amount propoitional, and preferably equal to the total distance of movement of a movable machine tool member to which an arm 14 of electric insulating material is rigidly attached. The insulating member 14 is provided with a series of cylindrical passages 32 arranged in closely spaced aligned relation for the reception of individual contact operating pins 16 of separate switch contacts. The present embodiment of the invention utilizes approximately twenty switch contacts which are unitarily movable, with the member to be controlled, between the ribs 3% and 31. Since all of the switches are identical only one will be specifically described.

The support member 10 has a plurality of slots 21, one for each of switch trip dogs 12', one for each switch contact operating pins 16, one for each pair of contacts 18 and 20. The switch trip dog 12 is releasably fixed by screw 22 to support ltl' in slot 21 until shoulder 33 of dog 12' engages surface 34 of support 10. Micrometer screw 23 is threaded into dog 12'. Advancing micrometer screw 23 resiliently expands surfaces 24 and 25 of dog 12'. A cylindrical passage 32 in insulating member 14' accommodates actuating 'pin 16. Upward movement of pin 16 brings the head portion 26 of pin 16 into abutting relationship with contact 18 which is secured to insulating member 14 by means of screw 29. Continued upward movement of pin 16 moves contact 18 out of engagement with contact 20 which is secured to insulating member 14 by screw 28. From the above description it is evident that movement of the support It) and the trip dog 12 to the right or left actuates the pin 16 to effect the operation of contacts 18 and 20. From the above description it is also evident that advancing micrometer screw 23 upward, resiliently expands dog 12, causing surfaces 24 and 25 of dog 12' to engage pin 16 earlier in its movement to the right or left thus providing accurate adjustment of the timing of the operation of the contacts 18 and 20.

Although the various features of the improved switch have beent shown and described in detail to fully disclose one embodiment of the invention, it will be evident that numerous changes can be made in such details, and certain features can be used without others, without departing from the principles of the invention.

I claim:

In a distance determining device, a frame; a plurality of parallel, spaced bars defining slots therebetween; a plurality of switches, each having a switch actuating plunger transversely in line with one of said slots; a dog including a body portion slidably mounted in each of said slots; means adapted to adjustably fix each of said dogs at any point along its corresponding slot; a cantilever portion having upwardly converging switch actuating surfaces mounted on said body portion; and means for moving said switch actuating surface relatively to its corresponding dog, whereby the point at which said switch actuating surface actuates the transversely movable plunger of its corresponding switch during relative rectilinear movement between said switches and frame may be adjusted independently of the means for adjustably fixing said dog along its corresponding slot.

References Cited in the file of this patent UNITED STATES PATENTS 

